A PRECISE METHOD FOR DETECTION OF VACUUM LEAKAGE IN A PRESSURE SENSORUSING A PULSE DISCHARGE TECHNIQUE, FOR INDUSTRIAL USE

A new method for measuring the vacuum leakage of a pressure sensor pro posed by the present authors has been improved so that it can be appli ed for industrial use. The principle of this method is based on the di scharge characteristic called Pashen's law. The main improved points a re reduction of fluctuation of the discharge potential and extension o f the measurable pressure range. As a result, a leakage rate of 1 x 10 (-5) Pa cm(3) s(-1) can be detected within a day. This sensitivity is comparable to that of the radio-isotope method now in practical use or even higher than that. The measurable pressure range is enlarged from 70-150 Pa to 70 Pa to a few hundreds pascals by employing He gas to d etect the leakage.